Antenna system



Oct. 3, 1933. J. B. DOW

ANTENNA SYSTEM Filed Aug. 20, 1950 )NVENTORJ AT ORNEY Q imlwli PatentedOct. 3, 1933 Q remnan s the at of time 3; 1833, as amended April 30,1928; 3'70 0. 757) 1 My invention relates broadly to directional radiocommunication systems I and j more I particularly to the constructionofan antenna for use in such systems.

-55 One or the objects of my invention is to provide a construction ofbeam antenna system for operation in directional signaling systemshaving a a minimum number ofparts and adapted to be readily erected andadjusted. j m

Another object of my inventionis to provide v. a simplified constructionor beam antenna for directive signaling systems adapted to be readilyadjusted for both long and short wave trans-1 mission and having meansfor adjusting the direction in which the antenna may be selectivelyoperated.-v 1 a Still another object of my invention is toprovide aconstruction of beam antenna wherein a multiplicityof reradiatorelements may be supported adjacent an antenna in such manner that theposition thereof. may be. readily changed for selectively fixingthedirection in which'th'e antenna is effective. o

Afurther object of myinvention is to provide a construction of beamantenna which may have the directionalcharacteristic thereof selectivelyadjusted by altering the positionof reradiat-- hereinafter following byreference to the accom panying drawing, in which:

Fig. 1 is a perspective view 'of the beam antenna systemof my invention;Fig. 2 isa fragmentary View showing one methodwhich I employ forremovably supporting the reradiator elemerits of the beam antennasystem;and Fig. 3 is a theoretical View illustrating the position of thereradiator conductors forselectively fixing the directionalcharacteristics of the antenna.

The beam antenna system of my invention has been developed for use inthedirectio'nal signaling systemset forth more fully in; my applicationNo. 70,162, .filed'July- 23, 1930. The beam antenna of my invention isadapted for both transmission and reception directionally. For

purposes of explaining the construction of the antenna system of myinventionv I shall describe the beam antenna particularly in connectionwith a transmission system. g

The beam antenna of my invention requires 5 only four rigidsupporting-members for the er'ecistics. of the antenna. l /ly inventioncontemmade to more nearlyapproach-a circle.

at intervals with insulators. The mast 2 is suittion of the beam antennafor the longestjwaves likely to be used. Heretofore it has been proposedtoerect large etructureswhich are actually shifted on a car runninguponrails forthe purposev or" changing the directional character--plates the erection of rigid supports without the necessity oferecting-a system of railsand mounting the antenna upon a moving carstructure operative upon such rails. The dire'ctivity' of the beamantenna of my invention is controlled by amultiplicity of reradiatorelementswhich are disposed in a portionjof a cylindrical envelopesurrounding the antenna conductor, The. reradiator elements areremovable from one p0 sition to another about the antenna conductor forselectively fixing the directional characteristicsof the antenna. I eReferring to the drawing in more detail, the four rigid supportsemployed in the beam antenna system of my invention are shown in theformof masts erected'at 1, 2, 3 and 4 in'the ground. I provide means forsupporting a'substantially circular frame member 5 between masts land.2.f A similar frame member is supported between masts 3 and 4 'asrepresented at 6 The frame members 5 and 6 may be formed-from wire orrope suspended in substantially cylindrical contour as shown. This isaccomplished by means of the guys or stays 'Z and S extending from theopposite mastsand connected to a mul tiplicity of points about the framemembers as p shown. By providing a substantial network of guys or stays'7 and 8 between masts 1 and 2 andv masts 3 and 4, the shape'oi frames 5and 6 is I The stays 7 connect with the frame 5 tending to stretch frame5 in a substantially circular shape.

Similarly the stays 8 extendingfrom masts 3 and 4 suspend the frame 6 ina substantially circular shape and by increasing the number of suchstays the shape is made to more-nearly approach a circle. The mast 1 ismaintained in a vertical position by guys represented at la suitablybroken f 1 ands! pass for raising the antenna conductor 12 insubstantially horizontal position. The antenna conductor is insulated atopposite ends as indicated. Leads 15 and '16 connect with the antennaconductor 12 and lead downwardly to the coupling inductance 17 which iscoupled. with inductance 18 leading to the circuit of the signalingapparatus 20.

In the arrangement illustrated the antenna is connected as a doublet fortransmission of signal-- ing energy. Other forms of connection betweenthe antenna and the signaling apparatusmay be employed if desired. Thereradiator elementsare adapted to be hoisted into position at selectedintervals around the frame members 5 and 6. I have indicated thereradiator elements at 21, 22, 23, 24, 25, 26, 2'7, 28 and 29. Eachreradiator element is constituted by ahorizontally disposed conductorextending parallel to the antenna conductor 12. The reradiator elementsare all adapted to be individually andremovably mounted between theframe members 5 and 6 by halyards passing over pulleys and insulatinglyconnected with the ends of the .reradiator elements. The reradiatorelement 21 is connected to insulators 21a at eachend thereof. Thehalyards 2117 are connected to the end of each of the insulatorsadjacent the remote ends. of the re'radiator. element 21 as shown moreclearly inFig. 2. The pulley 22a is secured to frame member 5 bymeans'of clamp 30. .A similar arrangement is provided at the op.- positeend of the antenna system so that each 'reradiator element may bereadily hoisted into position or removed from position for installationin another angular position with respect to the antenna conductor. Forthis purpose halya'rds are provided for each of the reradiator elementsrepresented at 2217,2325, 24b, 25b, 26b, 27b, 28b and 29b. Pulleys ofthe kind illustrated at 22a in Fig. 2 may be mounted at each point ofintersection of l the stays 7 with the frame member 5, and at each pointof intersection of the stays 8 with frame member 6 as I have representedat 31, 32, 33, 34, 35, 36 and 3'? with respect to frame member 5, and at38, 39, 40, 41,42, 43 and 44 with respect to frame member 6. Such aninstallation facilitates the. removal of a reradiator element from onevposition, and the installation of such a reradiator element in anotherposition according to the direction at which the signaling energy is tobe propagated as represented in the several examples indicated at Fig.3. In Fig. 3, the antenna condoctor is represented at 12 and the arrowextending therefrom serves to indicate the direction of propagation ofthe signaling energy due to the effect of the reradiator elements uponthe antenna conductor.

The dimensions of the antenna system of my invention depend upon thefrequency at which the system must operate. The minimum dimensionindicated at A is substantially one half ofthe longest radio wave lengthfor which the screen is designed. I have found it convenient to makedimension D substantially equal to A. Dimension Bshould preferably begreatenough to permit the radiated beam to clear nearby objects such asbuildings, etc., which might otherwise deflect the beam. The overalllength of the antenna and screen in a horizontal direction is indicatedby the dimension E.

While I have shown the antenna erected upon a horizontal axis, it willbe understood that the antenna may be mounted on avertical axis with thescreen surrounding the antenna conductor and the directivity of theantenna controlled by movable changing the positions of the rei'adiatorelements. It will be observed that the antenna structure of my inventiondiffers radically from beam antenna systems heretofore employed in thatI provide an arrangement for shifting the individual reradiator elementsconstituting the screen, whereas heretofore elaborate structures havebeen required for shifting the entire mass of a reflector adjacent theantenna conductor.

The antenna system of my invention has proven highly practical in itsconstruction and successful in' its operation, and while I havedescribed my invention in one of its preferred embodiments, I desirethat it be understood that modifications may be made and that nolimitations upon my invention are intended other than are imposed by thescope of the appended claims.

The invention herein described may be manufactured and used by or forthe Government of the United States of America for governmentalpurposeswithout the payment of any royalties thereon. i

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. A directive antenna system comprising supporting means, a pair ofsubstantially circular frame members carried by said supporting means,an antenna conductor extending axially of said frame members, pulleydevices secured at spaced intervals around each of said circular framemembers and a multiplicity of independently reconductors insulatinglysuspended through said'pulley devices between said frame members, fromeach endthereof for controlling the directive signaling properties ofsaid antenna conductor. I

2. A directive antenna system comprising supporting means erected atspaced intervals, sub stantially circular frames carried by saidsupporting means, pulley'devices secured at spaced intervals around eachof said circular frames in alignment with each other an antennaconductor extending axially of said substantially circular frames, and aplurality of independently-removable auxiliary conductors suspended bysaid pulley devices and disposedvaround the peripheries of saidsubstantially circular, frames equidistant from said antenna conductor,for controlling the directive signaling properties of said antennaconductor.

3. A directive antenna system comprising supporting means erected atspaced intervals, substantially circular frames carried by saidsupporting means and disposed in substantially vertical planes-parallelone to another, pulley devices mounted at spaced intervals around saidcircular frames an antenna conductor extendingaxially between saidframes in substantially horizontal direction, and a plurality ofindependently removable auxiliary conductors individually suspended bysaid pulley devices as elements of a circular cylinder defined by saidcircular frames and insulated one from another, for controlling thedirectional properties of said antenna conductor.

4. A directive antenna system comprising supporting means erected atspaced intervals, a pair of substantially circular frames carried bysaid supporting means, a plurality of pulley devices secured at spacedintervals in similar positions around each of said circular frames, aplurality of independent reflecting conductor elements, a plurality ofhalyards equal in number to twice the number of reflecting conductorelemembers disposed at spaced intervals in corre ment's, each of saidreflecting conductor elements being supported at each end by one of saidhal yards, each of said halyards passing through and being supported bya corresponding one ofsaid pulley devices, whereby any of saidreflecting conporting means, an antenna element extending axially ofsaid circular frames and normal to the planes thereof, apluralityofwireattachment antenna element.

spending positions around each of said circular frames, a plurality ofwire elements, each of said wire elements being connected at oppositeends thereof to the wire attachment members on said circular'frames atspaced intervals one withrespect to the other around said circularframes,

and means for selectively mounting orremoving said wire elements fromsaid wire attachment i members for selectively fixing the direction'iofpropagation of electromagnetic waves from said JENNINGS B. DOW.

